Performance Limits of a Polymer Matrix Nanocomposite as a Photoacoustic Transmitter for Retinal Stimulation

In a range of biomedical applications, polymer matrix nanocomposites (PMNCs) have been used as photoacoustic transmitters that emit acoustic pulses into surrounding media as a result of pulsed laser irradiation of the PMNC. The amplitude and frequency content of the emitted acoustic pulse depend on a range of factors including the optical, thermal and acoustic properties of the composite, the laser pulse characteristics, and the properties of the surrounding media. In this work, photoacoustic emission from a palladium-polydimethylsiloxane (Pd-PDMS) PMNC is studied to assess its use for acoustic stimulation of retinal tissues. For this application, the amplitude of the acoustic pulse should be maximized subject to various optical, thermal and acoustic constraints provided by the surrounding tissues and by the PMNC itself. Aspects of these constraints are considered in this work to provide important information for the design and use of retinal prosthetics.